(1) Field of the Invention
The present invention relates to a combined disc and shroud for a dual cyclonic cleaning apparatus. In particular the present invention relates to an apparatus which has an improved means for retaining dirt in an outer cyclonic container while allowing clean air to pass into a frusto-conically shaped inner cyclone.
(2) Prior Art
Cyclonic vacuum cleaning apparatus are shown in my U.S. Pat. Nos. 4,573,236, 4,593,429, 4,571,772 and 4,643,748. My U.S. Pat. No. 4,643,748 describes a dual cyclonic cleaning apparatus wherein a disc is mounted on the outside of a frusto-conically shaped inner cyclone in order to retain dirt in a first cyclonic cleaner. A separate shroud is provided for inlet of air into the second cyclone, including a moveable collar to dislodge accumulated dirt. A perforated inlet to the shroud has also been used on a cyclonic vacuum cleaner marketed in Japan in place of the collar. In these cleaners, the shroud and disc are separate from each other although both function to retain dirt particularly fibrous dirt in the container. The separate disc and shroud work well; however, there was a need for an improved design providing better separation of dirt in the outer cyclone than was achieved by the earlier apparatus.
It was found that by experimenting with the position of the holes and their location it was possible to reduce the blocking of the holes by fibrous particles.